Why did the dry wood split?

Just resawed a 20×7x7 part of a barn beam. Made little pieces 3×4x5. Brought them in the house which is about 50% humidity and in a day they have major splits in them. I was hoping to make a tractor bandsaw box with them.

What happened?

-- I came, I was conquered, I was born again. ἵνα ὦσιν ἓν

7 replies so far

Has the wood been outside at all, and changing climates for wood can cause all sorts of bad things to happen, and how drastic of a change in climate from where you were storing it previously is it to what your house is like?

-- Nick, "Choking to death on bacon is like getting murdered by your lover." - JG

Wood can do that, especially when super dry. Just like cutting the straps off a bundle of dry 2×2s. Once I ripped some 100+ year old nicely dried out 4×8 white oak into 2×4s – and to my surprise they did twist slightly (a few that didn’t were quarter-sawn).

If the wood was at 10 to 20% moisture content before you moved it into the 50 percent humididty it probably sucked up the humidity at different rates on top and bottom causing the warping, if enough tension is introduced into the wood the splits occur to relieve the stress. The other thing is if the barn beam was stable as a beam but once it was cut again internal stresses that were contained are now free to warp and twist and perhaps even crack the wood. Did the pieces with all four sides with new cuts warped differently than the boards with one or two ‘old’ faces?

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

Sometimes older wood just has built up internal tension that is able to cause cracking or warping after re sawing into smaller pieces so that tension can do its dastardly deeds. Also very likely moisture changes play into it as others said.

What happened is that the shell of the beam began to dry when you brought it inside at a much faster rate than the core because the beam was so thick. This sets up a lot of stress, and something had to give. Hence the splits.